Maple Sugar Industry Faces Unpredictability in the Face of Climate Change

Maple syrup has long been a delicious harbinger of spring and important industry, although scientists and maple producers are worried about the future of this temperature-dependent industry. That is because the cycle of cold temperatures at night and warmer temperatures during the day that are best for maple sugar production are less predictable than in years past, and have also resulted in a lower sugar content of the maple syrup. Sugar Bush and Red Maples trees are two of Signs of the Seasons “indicator species” due to the economic and social importance of understanding how their seasons are changing due to climate change.

Warming temperatures have lowered the sugar content of maple syrup, which means more sap is needed to make the product. For example, it used to take New Hampshire producers 25 gallons of sap to make a gallon of pure maple syrup, and now it takes 50 gallons.

Since 2014 the maple sugaring industry has been dealing with large variations in when the length of the season and when it begins. According to a 2016 USDA report on Northeast Maple Syrup production, 2014 saw the first tap on Jan. 10, and the season ended May 1. In 2015, the season ran for less then a month, March 18 to April 13. And in 2016, it ran from Jan. 27 to April 30.

Last year, some northern sugar houses actually had banner years, but overall production has decreased dramatically — from a peak of 4.2 million gallons of syrup produced in New Hampshire in the 1890s to less than 200,000 gallons in recent decades. A graph on the New Hampshire Maple Producers Association website, shows a slow steady decline over the past 60 years before rising slightly again in the past two or three years. In 2014, 112,000 gallons were produced; 154,000 gallons in 2015; and 169,000 gallons in 2016. However, that is far away from the high of 4.2 million gallons one hundred years ago!

The season will run as long as the region experiences a cycle of below-freezing and above-freezing temperatures. This change in temperature results in a change of pressure inside the trees and causes the sap to flow. Sugarers are hopeful that they can adapt to climate changes by adopting new farming techniques.

More information.

See the graph about NH Maple Sugar production (PDF).

Learn more about the phenophases of the red maples (acer rubrum) and sugar maples (acer saccharum).